1. Field of Invention
The present invention relates to anchors or fastening devices for affixing articles to the outer surfaces of solid materials and especially masonry materials.
2. Prior Art
The present invention is a bore gripping or engaging anchor structure of the type which is actuated by use of a blind rivet installation tool and is generally related to prior art presented in the following patents; WO8606447, DE3341266, EP0124489, DE2524459, DE2535237.
There are numerous advantages demonstrated by linearly actuated bore gripping anchors and fasteners as a group. One advantage of these types of fasteners is that there is no rotary component involved in coupling the anchor structure with a bore. This makes this type of fastener particularly well suited to application to bores in masonry materials and especially so to softer, more friable masonry materials. Another advantage that these anchors and fasteners offer is their inherent simplicity, both in application and in manufacture. Yet despite these advantages no prior art has combined the characteristics necessary to distinguish itself as a reliable and widely applicable, thus widely utilized anchor structure.
One object of the present invention is to provide an anchor structure which is easily installed, is simple, and is economic to manufacture, but to be widely applicable and utilized requires more than just simplicity of application and economy of manufacture. In addition it has to operate reliably and consistently over a wide range of bore gripping conditions, and to be truly versatile it should incorporate or enable a variety of article attachment options or article attachment means. That is to say that in addition to engaging and coupling with the wall of a bore it should offer a number of different methods by which to secure articles to the outer surface of the material of the bore.
Article attachment options and attachment means is a factor which is addressed to differing degrees in the prior art and which helps to differentiate the present invention as novel and improved. Though some patents cite only a fixed head, that is to say a radially enlarged portion which is integrally formed with the body of the device, other patents cite separable article attachment means, i.e. threaded elements as attachment means, and in some instances combinations of the two. One important factor which is overlooked in the prior art with integrally fixed heads is the need for a fixed head of an anchor structure to apply a certain amount of force between the head of the device and the outer surface of the material of the bore so as to pinch or hold an article to said surface. Hence another object of the present invention is to provide an anchor structure which has improved and novel attachment means.
As reiterated in many patents related to anchors and fasteners intended for application to bores in masonry materials, bores and holes drilled in these materials commonly have diametral values which vary substantially within a range of values for a given drill bit diameter. This is due to a number of factors, but one significant cause is that most common methods of drilling masonry materials can be generally described as material removal by rotary scraping, which results in a relatively rapid reduction of the diameter of the drill bits, due to the highly abrasive nature of many masonry materials. This requires an anchor structure intended for application to a bore drilled with a drill bit of a specific diameter to be able to operate reliably over a significant range of bore diameters. Additionally, masonry materials are very diverse in composition and characteristics, including strength and friability, so that a versatile anchor structure should be configurable to address a wide variety of bore engagement requirements. Thus it is another object of the present invention to provide an anchor structure which will operate effectively and reliable when applied to bores in masonry materials.